Real-time signal strength measurement and display of digital television signals

ABSTRACT

An HDTV receiver coupled to a terrestrial antenna displays real-time signal strength of terrestrial digital television signals. A graphical user interface preferably displays various data relating to all terrestrial television signals in a scrollable grid format. The grid is displayed within an active video display of a selected television signal from the grid. Audio for the selected channel is also active. A list of all channels tuned or selected is maintained to aid in searching. Channel lists are updated during certain channel searches.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.10/009,298, filed Dec. 4, 2001, now U.S. Pat. No. 6,985,190, and alsoclaims the benefit, under 35 U.S.C. § 365 of International ApplicationPCT/US00/15760, filed Jun. 8, 2000, which was published in accordancewith PCT Article 21(2) on Dec. 21, 2000 in English and which claims thebenefit of U.S. provisional patent application No. 60/139,467, filedJun. 16, 1999 and U.S. provisional patent application No. 60/143,341,filed Jul. 12, 1999, herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to digital television signals and, moreparticularly, to the receipt and measurement of off-air digitaltelevision signals.

2. Description of the Related Art

High Definition television (HDTV) sets and other digital digital set-topboxes must be able to receive digital signals, for example, terrestrialtelevision signals. Terrestrial digital television signals will bereceived by the television set typically in addition to digitaltelevision signals from other sources. These other sources, such ascable and satellite (i.e., DBS), generally provide television signals ata standard signal strength that is sufficient to allow the televisionreceiver to process and use the incoming digital television signal.

With both analog and digital off-air television signals, it is necessaryto connect an antenna to the television set. If several digital channelsare available, the user may be required to manually adjust the antennain order to receive the best possible reception from all availablechannels. It is known to provide a channel search routine that willobtain a discrete sample or “snapshot” of all the currently availablechannels on the various antenna inputs. The channel search routine thenstores the channels detected during the search in memory (e.g. EEPROM),deleting any channels previously stored that are not now currentlyavailable. At power-up of the unit, the channels in EEPROM become thechannel list. If the user were to adjust or relocate the antenna, thesignal strength of some digital signals (channels) may be too low totune (or receive). Therefore at power-up or if the user runs a channelsearch, various channels may be deleted. Further, weak channels areremoved to allow for the case where a user moves to another broadcastlocation (off-air, cable, or DBS).

It may be the case that several digital television signals are availableto the user but only if the antenna is manually adjusted to achieve thebest possible reception for the various channels. To efficiently achievethe best antenna placement, the user would need to know the signalstrengths of the various digital television channels. Also, with the useof a rotor and control electronics, the best position for the antennarelative to each digital television channel could be obtained, stored,and utilized, if the signal strength of each digital television channelwere known.

SUMMARY OF THE INVENTION

A dish pointing screen (an on-screen display or OSD) is currently usedin Digital Broadcast Satellite (DBS) products which indicates the dish'sorientation without concurrently displaying and/or reproducing theaudio/video signal or displaying the signal strength of off-air digitaltelevision channels. In one aspect of the present invention, thecurrently tuned channel may be displayed, in the background and itsrespective entry will be highlighted. If a valid channel is notdisplayed, then the first channel in the list may be highlighted.

In accordance with one aspect of the present invention, there isprovided a method and apparatus for displaying real-time signal strengthof off-air digital television signals. An Antenna Information (Info)program/routine preferably utilizing a graphical user interface isadapted to compile a list of received channels, to display signalstrength relating to any or all of the received digital channels inreal-time, and to play the audio and video of any particular channel,for any antenna input. Since audio and video are active during thereal-time display of signal strength, this allows the user to find thelowest signal strength that will provide an acceptable level of audioand video quality, i.e., a cut-off threshold. Finding the cut-offthreshold is particularly useful when digital broadcasts come fromdifferent directions and the terrestrial antenna cannot be pointed inboth directions.

In accordance with another aspect of the present invention, a user mayswitch to a different antenna input while the Antenna Informationroutine is active. Doing this will refresh the channel list to representthe available channels on the new antenna input. All of the channelsobtained by a channel search over a period of time are retained in anAntenna Information List for use by the Antenna Information routine.Antenna Information can thus be a listing of every channel that has everbeen added to a channel list by a channel search. For every channel inthe channel list, the Antenna Information routine will try to get thetuner (or selector) to connect to a signal on the various channelfrequencies. If the tuner is successful in receiving a usable televisionsignal, the channel is retained in the channel list. If the televisionsignal is digital, the strength of the signal will be at least measured,and possibly displayed.

The value of Antenna Info is to check the signal strength of digitalchannels while changing the antenna position. Antenna Info will usuallyinclude only the current antenna rather than both antennaesimultaneously.

In accordance with an aspect of the present invention, the user has theability to scroll through a list of channels that are currently in thechannel list. When any specific channel is selected, the tuner will playaudio and video for that channel, as the real-time signal strength isupdated on-screen (digital channels only). The list of channels that arecurrently available includes both analog and digital channels in orderto provide the user with an integrated channel screen where the effectsof an antenna adjustment on both digital and analog channels may beeasily seen.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by reference to the followingdrawings, wherein:

FIG. 1 depicts a multimedia system adapted to receive and utilizedigital television signals;

FIG. 2 is a program flow chart of a search routine invoked during aChannel Search in accordance with an aspect of the present invention;

FIG. 3 is a program flow chart of a search routine that adds a channelto the Channel List and Antenna Info List as a result of a discretedigital entry, in accordance with an aspect of the present invention;

FIG. 4 is a program flow chart of a power-up routine in accordance withan aspect of the present invention;

FIG. 5 is a program flow chart of a search routine invoked during anAntenna Info search in accordance with an aspect of the presentinvention; and

FIG. 6 is a depiction of a program screen as displayable on a displayunit particularly showing Antenna Information Results in accordance withan aspect of the present invention.

Corresponding reference characters indicate corresponding partsthroughout the several views.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, there is shown a simplified, functional blockdiagram of a multimedia system 10. Multimedia system 10 may include TVor monitor 12 and DBS and/or set-top box receiver 14, which is incommunication with TV 12 via communication line 16 as is known in theart. DBS (Direct Broadcast Satellite) receiver 14 is in communicationwith dish (or antenna) 18 via communication line 20 as is known in theart. Dish 18 receives digital multimedia and/or data signals, e.g.television, music and/or internet signals (hereinafter collectively“television signals”), that are focused onto and received byfeedhorn/LNA (Low Noise Amplifier) unit 22. Feedhorn/LNA unit 22typically receives and slightly amplifies the received televisionsignals and transmits the amplified television signals to DBS receiver14 for processing. DBS unit 14 may also be coupled to a CATV or cablesystem (not shown) via cable input line 24. TV 12 may be coupled toantenna or aerial 26 via communication line 28. Antenna 26 is designedto receive off-air or non-satellite broadcast digital or analogtelevision signals. As such, antenna 26 is generally adjustable eithermanually or automatically. The off-air television signals are fed intotuner 30 for discriminating or tuning the various channels and receivingany data signals as is known in the art.

Tuner 30 is in communication with microcontroller unit (“μC”) 32 suchthat digital television signals received from antenna 26 are receivedand processed by microcontroller unit 32 as is known in the art. Inaddition to other functions as are known in the art, microcontrollerunit 32 provides control and/or implementation of the various softwareprograms/routines and is in communication with various components inaccordance with the various aspects of the present invention.Microcontroller unit 32 is in communication with additional memory 34,e.g. EEPROM, RAM, ROM, and display 36. TV 12 may also include left andright speakers 38 a and 38 b, respectively, coupled to microcontrollerunit 32 via audio communication lines 40 a and 40 b, respectively, forproviding audio output for the user.

Additionally, microcontroller unit 32 includes the ability to generate,process, and display OSD information/data on display 36. The OSDinformation/data may be part of a received television signal or may begenerated internally. Such OSD information may include channel number,time, signal strength, on-screen electronic program guides (EPGs),internet data, pop-up windows, on-screen electronic programming menus,and the like. Microcontroller unit 32 also runs various softwarenecessary to process and/or utilize the incoming digital signals as isknown in the art and additionally as provided herein.

It should be understood that microcontroller unit 32 by itself or alongwith tuner 30 and memory 34 form a module capable of implementing thepresent invention. This module may be totally separate (discrete module)or may incorporate existing constituents of the various components(virtual module). In this manner, the module may be incorporated into TV12, DBS/Set-Top Receiver Unit 14, or any other digital component capableof receiving and/or utilizing digital television signals.

Referring now to FIG. 6 there is depicted display 36 showing programscreen 44. Program screen 44 is an exemplary screen indicative of atypical programming/menu/information (“program”) screen into which thepresent invention may be incorporated. Included on program screen 44 isa plurality of menu items/programs/functions 50 available for possibleselection by the user and implementation by the unit. In accordance withan aspect of the present invention, one such menu item 50 is “AntennaInfo” (Antenna Information) 52.

Antenna Info 52 is a menu choice for invoking the Antenna Informationprogram, function or routine from a main or auxiliary screen or througha separate button on a remote. Upon selection of Antenna Info either bybutton or menu choice, context sensitive textual help may be displayedon a portion of program screen 44 to assist the user.

The Antenna Information process provides real-time signal strength ofthe received digital signal (e.g., terrestrial or satellite televisionsignals) and helps the user adjust his terrestrial antenna (e.g.,antenna 26 of FIG. 1) to receive the greatest number of digitaltelevision channels that satisfy a minimum signal strength threshold.Therefore, the actual adding of both analog and digital channels to thecurrent tuning capability of the television or set-top box and thebuilding of a Channel List representative thereof, is done by theChannel Search function/routine. The search performed by Antenna Infomay be separate from the Channel Search function and may be invoked fromanother program screen. When a signal or channel scan is performed bythe Channel Search routine, only those analog and digital channels thathave a signal strength above a certain threshold criterion is added tothe Channel List which is stored in memory (e.g., EEPROM). The ChannelList is thus a stored list of currently available analog and digitaltelevision channels that will be displayed during channelscanning/surfing by the user.

The actions performed by a Channel Search may be summarized by thefollowing table, which identifies what occurs to the Channel List and

Action Channel List Antenna Info List Find good channel Add Add Find badchannel Remove No-Changethe Antenna Info List which is stored separately from the Channel Listand utilized for a different purpose during a Channel Search. Withadditional reference to FIG. 2, there is depicted program flow chart 70for the Channel Search routine. Upon selection, the Channel Search isstarted 72 and the next frequency starting from a chosen frequency isscanned 74. If there is not a next frequency, the routine is done 76.When a next frequency is encountered, it is determined whether there isa usable signal on the frequency/channel 78. Usable may be determined byapplying a threshold signal strength for the incoming signal to overcomeor other parameter or set of parameters. For each incomingfrequency/channel that does not meet threshold signal strengthrequirements or otherwise, the channel is removed from the Channel List75 and a next frequency is determined 74. A continuous non-receipt ofusable channels results in a loop until there are no more nextfrequencies available. For each incoming frequency/channel that meetsthe threshold signal strength requirements or otherwise, the channel isadded to the Channel List and the Antenna Info List in step 80. Theprocess repeats until there is no next frequency as determined in step74.

With reference to FIG. 3 there is depicted a program flow chart 82 forautomatically adding channels to the Channel List. When a user inputsdiscrete digits for a particular channel 84, generally from a keypad ofa remote (not shown), the program begins. Upon receipt of the channelnumber, it is determined whether there is a usable signal on thefrequency/channel 86. If there is no usable signal, the programterminates 88. If there is a usable signal that channel is added to theChannel List and the Antenna Info List 90.

With reference to FIG. 4 there is depicted a program flow chart 92 foradding channels to the Antenna Info List, generally unbeknownst to theuser. When the power to the unit is turned on at step 94 the nextchannel that is in EEPROM is scanned to determine if there is anavailable signal 96. If not, the program terminates 98. If a usablesignal exists (is available), it is added to the Antenna Info List 100.Thereafter the program determines if another channel is available forviewing. These routines thus add usable channels to the Channel List aswell as the Antenna Info List.

The actions performed by an Antenna Info search may be summarized by thefollowing table which, identifies what occurs during an Antenna Infosearch when a good strength signal is received (usable) or a badstrength signal is received (low or none).

Action Channel List Antenna Info List Find good channel Add UpdateSignal Strength Find bad channel No Change Update Signal Strength

FIG. 5 is a flow chart of the Antenna Info Search routine 104. Uponstart of the Antenna Info search 106, the next frequency/channel in theAntenna Info List is scanned for a signal 108. If there are no morefrequencies/channels and/or it is the end of a predetermined list, theprogram terminates 110. If a usable signal exists on the channel it isdetermined whether it is an analog or digital signal 112. An analogsignal is added (posted) to the Channel List 114. Thereafter, the unitis ready to scan to the next frequency 108. If the signal is digital,the signal strength is measured in real-time and is updated in theAntenna Info List, and the channel is added to the Channel List 116.Thereafter, the unit is ready to scan to the next frequency 108.

At the same time the various Antenna Info screens are prompting theuser, channel data grid 54 will fill with information about thechannels, one per row 64, that are being received or have been receivedfrom all terrestrial antenna(s), namely, the channel number, column 58;the station name (e.g., NBC [if possible] in column 60); whether thechannel is digital or analog, column 58; which antenna is picking up thechannel, column 60, and for the digital channels only, their currentsignal strength, column 62. Other types of information may also bedisplayed regarding the various channels. Channel data grid 54 includesscreen name 56 (Antenna Info) and displays a number of rows, here fiverows 64 a-e, at one time. Arrows 67 and 68 indicate there are morechannels viewable through scrolling up or down the grid.

The Antenna Info screen will retain those channels that were previouslymeasured in a past Antenna Info measurement process but aren't ofsufficient strength to pass the “signal-strength thresholdcriterion/level” to be added to a channel list from a Channel Search.This is desirable since users may not know what local channels areavailable, but once they know which channels are available, it is up tothe discretion of the user whether to try and adjust their antenna(s) tomake certain channels have sufficient strength to be added to a ChannelSearch list.

Once the signal strength measurement is complete, the Antenna InfoResults Screen shown in program screen 44 will be shown on display 36.The user can navigate through the grid defined by the channel number andtheir various attributes or characteristics (rows 64 and columns 58, 60,62) by scrolling up and down the looping/wrap-around list to see whatchannels are available using the current antenna position. Those digitalchannels with, for example, a “-” instead of a number indicate that thesignal strength is neither sufficient for viewing the channel nor foradding the channel to a Channel List from a Channel Search, see 64 d.All analog channels will have “N/A” appear as their strength to indicatethat signal strength measurement is not available for those channels(see 64 c). Those channels that are currently unavailable through aChannel Search can appear in the list from previous signal strengthmeasurements or appear in the list from information obtained from aguide or as otherwise indicated herein.

If the user selects the “Antenna Info” function, then the signalstrength for that channel will be measured and/or updated. As the userscrolls through different channels, the tuner tries to connect to thechannel that is highlighted. If the channel is detected, the signalstrength measurement is taken and/or updated. At no time are channelsautomatically discarded for insufficient signal strength, this helps theuser to know what channels are available and to try and adjust theantenna(s) to make channels have sufficient signal strength to be addedto the channel list.

The list may be sorted from lowest channel number at the top to highestchannel number at the bottom. For channels where an analog and a digitalchannel share the same virtual channel number, the analog channelappears adjacent to the digital channel in the list.

The user can update the information for each channel simply by movingthe highlight to that channel in the Antenna Info screen (see 64 b). Inaddition, the video behind the Antenna Info display area will show thecurrent channel, including audio, to assist the user in making antennaadjustments. To change antennas or antenna input, the user pressesANTENNA on the remote or by menu choice. Each time a full Antenna InfoSearch is performed the signal strengths for all digital channels willbe measured. Each highlighted channel in the grid has its signalstrength updated in real-time as the audio and video for that channelare being played behind program screen 44 on display 36. In analternative embodiment the signal strength of each available channel isnot automatically displayed. The signal strength will be displayed uponselection of the channel.

When the signal strength measurement process is complete, a dialog boxwill appear on display 36, typically superimposed or within the currentscreen. When the user selects “Continue”, the highlight in the AntennaInfo screen will move to the first channel row (64 a) in channel datagrid 54. If the user aborts the signal measurement process, a dialog boxis displayed informing the user and the displayed strengths in channeldata grid 54 are whatever was determined until the moment that theprocess was aborted.

When the channel in the list is highlighted (64 b), the informationabout the channel is continually updated. This is particularly useful inthe case where a digital channel that is transmitting a Program andSystem Information Protocol (PSIP) (ATSC document A/65) guide changesthe channel lineup to include an analog channel with the same majorchannel number (briefly define major channel) as the digital channel. Inthis case, the Antenna Info list will expand to include this new analogchannel as a separate entry (row 64) in channel data grid 54. The newanalog channel will have the same channel number as the digital channel,but will be marked as an analog channel in column 58, as opposed tobeing marked a digital channel. This update and expansion of the list istotally automatic and in real-time.

In order to align the terrestrial antenna to obtain the best signalstrength for a given set of digital channels, it will be most likelynecessary to perform an Antenna Info Search several times for eachterrestrial antenna receiving digital television signals. Signalstrengths for the various digital television channels will need to bemonitored with relation to the orientation of the antenna while theantenna is being positioned. By performing the Antenna Info Search manytimes, an optimum antenna position may be found. After the antenna hasbeen positioned accordingly, it is necessary to perform a Channel Searchto add the channels to the Channel List.

An example will illustrate the above principles. A new terrestrialantenna (ref. antenna 26, FIG. 1) adapted to receive off-air digitaltelevision signals, is coupled to a receiving unit (ref. TV 12, FIG. 1).Assume that after power-up the initial state of both the Channel Listand the Antenna Info List are empty. A Channel Search is run by the userduring initial setup of the unit or because several new channels havebeen added after a previous Channel Search. The initial Channel Searchlocates two channels having signals above a given threshold level forminimal reception, namely channels “10” and “20”. At this point, ChannelList contains channels “10” and “20”, and the Antenna Info List containschannels “10” and “20”. The user then adjusts antenna 26 and performsanother Channel Search. This search locates two additional channelshaving signals above a given threshold level for minimal reception,namely channels “30” and “40”, but did not detect previous channels “10”and “20” because of the new antenna orientation. Now, Channel Listcontains channels “30” and “40”, while Antenna Info List containschannels “10”, “20”, “30”, and “40”. Since the user knows there are fourchannels available, an Antenna Info Search is run each time the positionof the antenna is altered slightly to try to determine an optimalposition of the antenna. Channel “10” will be checked in accordance withthe program flow chart of FIG. 5. Assume that now channel “10” has asignal strength greater than the predetermined threshold. Therefore,channel “10” is added to Channel List making the contents of ChannelList channels “10”, “30”, and “40”, while the Antenna Info List does notchange. Another adjustment to the antenna and another Antenna InfoSearch is performed. Assume that now channel “20” now has a signalstrength greater than the predetermined threshold. Channel “20” is addedto Channel List making the contents of both Channel List and AntennaInfo List channels “10”, “20”, “30”, and “40”.

While this invention has been described as having a preferred design,the present invention can be further modified within the scope of thisdisclosure. This application is therefore intended to cover anyvariations, uses, of adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art.

1. A video processing apparatus comprising: means for receiving aplurality of television signals having audio and video informationcomponents and selecting a television signal from the plurality ofreceived television signals; means for displaying the video informationcomponent of a selected said television signal on a display devicecoupled to said video processing apparatus; means for determining signalstrength of each one of the plurality of said received televisionsignals; and means for selectively displaying the signal strength of theplurality of said received television signals while the audio and videoof the selected television signal is active.
 2. The video processingapparatus of claim 1, wherein said means for selectively displayingincludes means for selectively displaying signal strengths of each oneof the plurality of received television signals in a grid format whilethe audio and video of the selected television signal is active.
 3. Thevideo processing apparatus of claim 1, wherein said means forselectively displaying includes means for selectively displaying whethereach of said plurality of received television signals is analog ordigital.
 4. The video processing apparatus of claim 2, furthercomprising: means for updating in real-time the signal strength of theselected television signal.
 5. The video processing apparatus of claim1, further comprising: means for storing in memory a channel numberassociated with the received television signals when the signal strengthexceeds a predetermined threshold level.
 6. A method of positioning anantenna for receiving digital television signals comprising: a.selecting an initial position for said antenna; b. displaying the signalstrength of each one of the plurality of received digital televisionsignals concurrently; and c. selecting a final reception position forsaid antenna based on the measured signal strength of at least one ofsaid plurality of received digital television signals.
 7. The method ofclaim 6, wherein the step of selecting an initial position and the stepof displaying is repeated until the signal strength of a set of receiveddigital television signals is optimized.
 8. The method of claim 6,wherein the received digital television signals are concurrently audibleand viewable during real-time display of signal strength for a selectedchannel.